8 ON CORAIi REEFS AND ISLANDS. 



Above Angau lies Nairai; though a smaller island than Angau 

 the barrier reef is of greater extent, and stretches off far from the 

 shores. To the eastward of Nairai are Vatu Rera, Chichia, and 

 Naiau, other examples of islands fringed around with narrow 

 reefs. Lakemba, a little more to the southward, is also encircled 

 with coral : but on the east side the reef is a distant barrier. In 

 Aiva, immediately south of Lakemba, the same structure is ex- 

 emplified ; but the coral ring is singularly large for the little spots 

 of land it encloses. The Argo Reef, east of Lakemba, is a still 

 larger barrier, encircling two points of rock called Bacon's isles. 

 It is actually a large lagoon island, twenty miles long, with some 

 coral islets in the lagoon, and two of basaltic constitution, of 

 which the largest is only a mile in diameter, Aiva and Lakemba 

 are in fact other lagoon islands, in which the rocky islands of the 

 interior bear a larger proportion to the whole area. The same 

 view is further illustrated by comparing the Argo reef with Nairai, 

 Angau, or Moala : these cases differ only in the greater or less dis- 

 tance of the reef from the shores and the extent of the enclosed 

 land. 



Passing to the large islands Vanua Levu and Viti Levu, we 

 observe the same peculiarities illustrated on a much grander scale. 

 Along the southern shores of Viti Levu, the coral reef lies close 

 against the coast ; and the same is seen on the east side and north 

 extremity of Vanua Levu. But on the west side of these islands, 

 this reef stretches far off from the land, and in some parts is even 

 twenty-five miles distant, with a broad sea within. This sea, 

 however, is obstructed by reefs, and along the shores there are 

 proper fringing reefs. 



The forms of encircling reefs depend evidently to a great ex- 

 tent on that of the land they enclose. That this is the case even 

 in the Argo reef and such other examples as offer now but a sin- 

 gle rock above the surface of the enclosed lagoon, we shall en- 

 deavor to make apparent, if not. already so, when the cause of the 

 forms of coral islands is under discussion. Yet it is also evident 

 that this correspondence is not exact, for many parts of the 

 shores, and sometimes more than half the coast, may be exposed to 

 the sea, while other portions are protected by a wide barrier. 



In recapitulation, we remark, that reefs around islands may be 

 (1) entirely encircling; or they may be (2) confined to a larger 

 or a smaller portion of the coast, either continuous or interrupted : 

 they may (3) constitute throughout a distant barrier ; or (4) the 

 reef may be fringing in one part and a barrier in another ; or (5) 

 it maybe fringing alone: the barrier maybe (6) at great dis- 

 tances from the shores, with a wide sea within, or (7) it may so 

 unite to the fringing reef that the channel between will hardly 

 float a canoe. These points are sustained by all reef regions. 





